I just knocked together a very quick and dirty tutorial for getting a face from a poly modeling or polysculpting software to MOI NURBS model. Sorry that it turned out a bit ugly. Only have GIMP installed on this machine so it was a monumental struggle to lay this out. =P

This is more or less how my head started, even though I completely resurfaced it a couple of times with new curves.

This could actually be semi-automated in the obj23dmwireframe tool if it automatically deleted any edge more vertical than say 45 degrees to the horizontal and just left the horizontal edges useful for curve creation. A choice of horizontal or vertical lines wouldn't be bad either.

Hope some of you find this useful, even though it is annoyingly manual.